(a) Field of the Invention
The present invention relates to a liquid crystal display and a thin film transistor array panel therefor.
(b) Description of the Related Art
A liquid crystal display (LCD) is one of the most widely used flat panel displays. An LCD includes a liquid crystal (LC) layer interposed between a pair of panels provided with field-generating electrodes. The LC layer is subject to an electric field generated by the electrodes and variations in the field strength change the molecular orientation of the LC layer, which in turn change the polarization of light passing through the LC layer. Appropriately disposed polarizer(s) change the light transmittance based on the polarization of the light.
One measure of LCD quality is a viewing angle that is defined by angle where the LCD exhibits a predetermined contrast ratio. Various techniques for enlarging the viewing angle have been suggested, including a technique utilizing a vertically aligned LC layer and providing cutouts or protrusions at the field-generating electrodes such as pixel electrodes and a common electrode.
However, cutouts and the protrusions reduce the aperture ratio. To increase aperture ratio, it has been suggested that the size of the pixel electrodes be maximized. However, maximization of the size of the pixel electrodes results in a close distance between the pixel electrodes, causing strong lateral electric fields between the pixel electrodes. The strong electric fields cause unwanted altering of the orientation of the LC molecules, yielding textures and light leakage and deteriorating display characteristics. The textures and the light leakage may be screened by a wide black matrix, which also reduces the aperture ratio.
In the meantime, the size of the pixel electrodes is increased as the LCD increases. The shape of the pixel electrodes is not recognized when the pitch of the pixel electrodes is small, for example, smaller than about 100 microns. However, the outline of the pixel electrodes defined by signal lines such as an oblique outline may be perceived when the pitch of the pixel electrodes becomes large, for example, larger than about 100 microns, thereby deteriorating display characteristics. In addition, the oblique shape of the pixel electrodes may weaken a driving electric field to liquid crystal molecules located at some positions to increase the response time.